Problem: On the way to school, Karen became fixated on the puzzle game on her phone!

<image>

The game is played as follows. In each level, you have a grid with n rows and m columns. Each cell originally contains the number 0.

One move consists of choosing one row or column, and adding 1 to all of the cells in that row or column.

To win the level, after all the moves, the number in the cell at the i-th row and j-th column should be equal to gi, j.

Karen is stuck on one level, and wants to know a way to beat this level using the minimum number of moves. Please, help her with this task!

Input

The first line of input contains two integers, n and m (1 ≤ n, m ≤ 100), the number of rows and the number of columns in the grid, respectively.

The next n lines each contain m integers. In particular, the j-th integer in the i-th of these rows contains gi, j (0 ≤ gi, j ≤ 500).

Output

If there is an error and it is actually not possible to beat the level, output a single integer -1.

Otherwise, on the first line, output a single integer k, the minimum number of moves necessary to beat the level.

The next k lines should each contain one of the following, describing the moves in the order they must be done:

  * row x, (1 ≤ x ≤ n) describing a move of the form "choose the x-th row". 
  * col x, (1 ≤ x ≤ m) describing a move of the form "choose the x-th column". 



If there are multiple optimal solutions, output any one of them.

Examples

Input

3 5
2 2 2 3 2
0 0 0 1 0
1 1 1 2 1


Output

4
row 1
row 1
col 4
row 3


Input

3 3
0 0 0
0 1 0
0 0 0


Output

-1


Input

3 3
1 1 1
1 1 1
1 1 1


Output

3
row 1
row 2
row 3

Note

In the first test case, Karen has a grid with 3 rows and 5 columns. She can perform the following 4 moves to beat the level:

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In the second test case, Karen has a grid with 3 rows and 3 columns. It is clear that it is impossible to beat the level; performing any move will create three 1s on the grid, but it is required to only have one 1 in the center.

In the third test case, Karen has a grid with 3 rows and 3 columns. She can perform the following 3 moves to beat the level:

<image>

Note that this is not the only solution; another solution, among others, is col 1, col 2, col 3.

Solution (in PYTHON):

Solution:
def main():
    n,m=list(map(int,raw_input().strip().split(' ')))
    Mat=[]
    bound=0
    MINMOVE=[]
    for j in range(n):
        temp=list(map(int,raw_input().strip().split(' ')))
        if j==0:
            bound=min(temp)
        Mat+=[temp]


    for k in range(0,bound+1):
        r=[0 for i in range(n)]
        shit=0
        r[0]=k
        copy=[]
        for i in range(n):
            temp=Mat[i][:]
            copy+=[temp]
            
        for j in range(m):
            copy[0][j]-=k
            
                


        check=0
        for i in range(1,n):
            r[i]=r[0]+Mat[i][0]-Mat[0][0]
            if r[i]<0:
                check=1
                break
            for j in range(m):
                copy[i][j]-=r[i]
        if check==1:
            continue
        col=[0 for i in range(m)]

        for j in range(m):
            if shit==1:
                break
            col[j]=copy[0][j]
            for i in range(n):
                if copy[i][j]!=col[j]:
                    shit=1
                    break

        if shit==0:
            #print(r,col)
            total=0
            for i in range(n):
                total+=r[i]
            for j in range(m):
                total+=col[j]
            #print(total)    
            if MINMOVE==[]:
                MINMOVE=[total,r,col]
            else:
                if total<MINMOVE[0]:
                    MINMOVE=[total,r,col]
            
            
            
            #for i in range(n):
            #    for _ in range(r[i]):
            #        print 'row',i+1
            #for j in range(m) :
            #    for _ in range(col[j]):
            #        print 'col',j+1
            #return 0
    if MINMOVE==[]:        
        print(-1)
    else:
        #print(MINMOVE)
        total,r,col=MINMOVE
        print(total)
        for i in range(n):
            for _ in range(r[i]):
                print 'row',i+1
        for j in range(m):
            for _ in range(col[j]):
                print 'col',j+1
                
            
main()